Water-repellent coatings are frequently applied to the windows of vehicles, in particular to the windshields, to improve visibility under wet conditions, e.g., in the event of rain or snow. The hydrophobic properties of water-repellent compounds involve a high wetting angle causing droplets distributed on the window to run together to form large round drops which have a low adhesion to the windows. These drops can be easily removed from the window by the action of a wiper. At higher speeds, a wiper is not even necessary since the drops are removed from the window by the action of the airstream.
The water-repellent coatings are generated by the application of a water-repellent fluid. Various application options exist, e.g., applying the fluids by means of a cotton cloth, that is to say distributing the fluid manually on the window, or spraying it on. However, to this end, the window has to be coated manually each time when the water-repellent effect diminishes. This is very laborious. Further options exist for the application of hydrophobic fluid or hydrophobic particles to the window and the distribution thereof by means of the wiper. To this end, for example, hydrophobic particles can be distributed in the material of the wiper, these being applied to, and distributed on, the window continuously upon a movement of the wiper. (For example, see US2008/0040880A1 and US2013/0045332A1). However, to this end, the material of the wiper has to likewise be refilled regularly. A hydrophobic material is moreover applied continuously irrespective of requirement. The object, therefore, is to coat the windows mechanically in a controlled manner when required.